kernel: copy kernel 4.19 code to 5.4

No changes were done to the patches while coping them. Currently they do
not apply on top of kernel 5.4.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

1 files changed, 137 insertions, 0 deletions

diff --git a/target/linux/generic/pending-5.4/304-mips_disable_fpu.patch b/target/linux/generic/pending-5.4/304-mips_disable_fpu.patch
new file mode 100644
index 0000000000..332bb71e22
--- /dev/null
+++ b/target/linux/generic/pending-5.4/304-mips_disable_fpu.patch
@@ -0,0 +1,137 @@
+From:   Manuel Lauss <manuel.lauss@gmail.com>
+Subject: [RFC PATCH v4 2/2] MIPS: make FPU emulator optional
+
+This small patch makes the MIPS FPU emulator optional. The kernel
+kills float-users on systems without a hardware FPU by sending a SIGILL.
+
+Disabling the emulator shrinks vmlinux by about 54kBytes (32bit,
+optimizing for size).
+
+Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
+---
+v4: rediffed because of patch 1/2, should now work with micromips as well
+v3: updated patch description with size savings.
+v2: incorporated changes suggested by Jonas Gorski
+    force the fpu emulator on for micromips: relocating the parts
+    of the mmips code in the emulator to other areas would be a
+    much larger change; I went the cheap route instead with this.
+
+ arch/mips/Kbuild                     |  2 +-
+ arch/mips/Kconfig                    | 14 ++++++++++++++
+ arch/mips/include/asm/fpu.h          |  5 +++--
+ arch/mips/include/asm/fpu_emulator.h | 15 +++++++++++++++
+ 4 files changed, 33 insertions(+), 3 deletions(-)
+
+--- a/arch/mips/Kconfig
++++ b/arch/mips/Kconfig
+@@ -2893,6 +2893,20 @@ config MIPS_O32_FP64_SUPPORT
+ 
+ 	  If unsure, say N.
+ 
++config MIPS_FPU_EMULATOR
++	bool "MIPS FPU Emulator"
++	default y
++	help
++	  This option lets you disable the built-in MIPS FPU (Coprocessor 1)
++	  emulator, which handles floating-point instructions on processors
++	  without a hardware FPU.  It is generally a good idea to keep the
++	  emulator built-in, unless you are perfectly sure you have a
++	  complete soft-float environment.  With the emulator disabled, all
++	  users of float operations will be killed with an illegal instr-
++	  uction exception.
++
++	  Say Y, please.
++
+ config USE_OF
+ 	bool
+ 	select OF
+--- a/arch/mips/Makefile
++++ b/arch/mips/Makefile
+@@ -323,7 +323,7 @@ OBJCOPYFLAGS		+= --remove-section=.regin
+ head-y := arch/mips/kernel/head.o
+ 
+ libs-y			+= arch/mips/lib/
+-libs-y			+= arch/mips/math-emu/
++libs-$(CONFIG_MIPS_FPU_EMULATOR)	+= arch/mips/math-emu/
+ 
+ # See arch/mips/Kbuild for content of core part of the kernel
+ core-y += arch/mips/
+--- a/arch/mips/include/asm/fpu.h
++++ b/arch/mips/include/asm/fpu.h
+@@ -230,8 +230,10 @@ static inline int init_fpu(void)
+ 		/* Restore FRE */
+ 		write_c0_config5(config5);
+ 		enable_fpu_hazard();
+-	} else
++	} else if (IS_ENABLED(CONFIG_MIPS_FPU_EMULATOR))
+ 		fpu_emulator_init_fpu();
++	else
++		ret = SIGILL;
+ 
+ 	return ret;
+ }
+--- a/arch/mips/include/asm/fpu_emulator.h
++++ b/arch/mips/include/asm/fpu_emulator.h
+@@ -30,6 +30,7 @@
+ #include <asm/local.h>
+ #include <asm/processor.h>
+ 
++#ifdef CONFIG_MIPS_FPU_EMULATOR
+ #ifdef CONFIG_DEBUG_FS
+ 
+ struct mips_fpu_emulator_stats {
+@@ -179,6 +180,16 @@ do {									\
+ extern int fpu_emulator_cop1Handler(struct pt_regs *xcp,
+ 				    struct mips_fpu_struct *ctx, int has_fpu,
+ 				    void __user **fault_addr);
++#else	/* no CONFIG_MIPS_FPU_EMULATOR */
++static inline int fpu_emulator_cop1Handler(struct pt_regs *xcp,
++				struct mips_fpu_struct *ctx, int has_fpu,
++				void __user **fault_addr)
++{
++	*fault_addr = NULL;
++	return SIGILL;	/* we don't speak MIPS FPU */
++}
++#endif	/* CONFIG_MIPS_FPU_EMULATOR */
++
+ void force_fcr31_sig(unsigned long fcr31, void __user *fault_addr,
+ 		     struct task_struct *tsk);
+ int process_fpemu_return(int sig, void __user *fault_addr,
+--- a/arch/mips/include/asm/dsemul.h
++++ b/arch/mips/include/asm/dsemul.h
+@@ -41,6 +41,7 @@ struct task_struct;
+ extern int mips_dsemul(struct pt_regs *regs, mips_instruction ir,
+ 		       unsigned long branch_pc, unsigned long cont_pc);
+ 
++#ifdef CONFIG_MIPS_FPU_EMULATOR
+ /**
+  * do_dsemulret() - Return from a delay slot 'emulation' frame
+  * @xcp:	User thread register context.
+@@ -88,5 +89,27 @@ extern bool dsemul_thread_rollback(struc
+  * before @mm is freed in order to avoid memory leaks.
+  */
+ extern void dsemul_mm_cleanup(struct mm_struct *mm);
++#else
++static inline bool do_dsemulret(struct pt_regs *xcp)
++{
++	return false;
++}
++
++static inline bool dsemul_thread_cleanup(struct task_struct *tsk)
++{
++	return false;
++}
++
++static inline bool dsemul_thread_rollback(struct pt_regs *regs)
++{
++	return false;
++}
++
++static inline void dsemul_mm_cleanup(struct mm_struct *mm)
++{
++
++}
++
++#endif
+ 
+ #endif /* __MIPS_ASM_DSEMUL_H__ */